To setup the tests:
virtualenv .venv
. .venv/bin/activate
pip install nose redis eventlet
Then you can repeatedly run:
nosetests
To install the package redismultiwrite onto your system:
sudo python setup.py install
Create redis.StrictRedis[1]
objects for the local datacenter redis instance. This object will be the
authoritative connection, and will determine the success or failure of
subsequent functions.
Then create a list of redis.StrictRedis objects for each remote datacenter
redis instance. Cross-datacenter commands will also propogate to these
connections before return. Create the redismultiwrite.RedisMultiWrite object
using these two pieces of information:
local = redis.StrictRedis(host='localhost')
remote = [redis.StrictRedis(host='redis.example.com')]
conn = redismultiwrite.RedisMultiWrite(local, remote)
The new RedisMultiWrite object will functionally mimic a StrictRedis object,
routing all standard calls to the local StrictRedis object.
The RedisMultiWrite object will also allow each method to be suffixed with
_everywhere. These methods correspond to the original, with the added benefit
of simultaneously being performed against all the remote redis connections.
For example, if I called delete_everywhere, a DELETE command would be sent
to every supplied local and remote redis connection. However, only the local
redis connection's response will be returned (or thrown) by
delete_everywhere. The responses or exceptions generated by remote redis
connections will be logged and discarded.
If the optional flag wait_for_remote to the RedisMultiWrite
constructor is given True, then the _everywhere methods will wait until each
remote connection has completed. By default, the functions return as soon as the
local connection has finished and remote connections continue to wait in the
background.
For transactions (like the pipe() method of StrictRedis), there is a method
pipe_everywhere(). This command takes a sequence of two-item tuples: a command
string and a tuple of argument strings. For example:
conn.pipe_everywhere([('get', ('mykey', )),
('delete', ('mykey', ))])
This library uses eventlet to perform simultaneous socket operations.